The field of the invention pertains to commercial size riding lawnmowers, and, in particular, to lawnmowers that have a zero turn radius and lever steering control for the operator. Such mowers will spin about a vertical axis equidistant between drive wheels when the drive wheels are driven in opposite directions with the same rotational speed.
Zero turn radius mowers are often constructed with the drive wheels approximately equidistant from the front and rear of the mower and a large caster wheel adjacent the back of the mower. Examples of such zero turn radius mowers are disclosed in applicant's previous U.S. Pat. Nos. 4,395,865 and 4,429,515 and these patents are incorporated herein by reference.
Zero turn radius mowers such as applicant's above are traditionally controlled for forward, reverse and steering by a pair of lever arms mounted on transverse pivots. The lever arms are to either side of the operator and therefore require the operator to use both hands on the levers to operate the mower.
Single lever "joy sticks" have also been used to control zero turn radius mowers. Joy stick control offers a full range of speed and steering control with one hand, however, full range control with a joy stick results in "hunting" for the right combination of speed and turn to reach a specific goal. Tracking the mower straight at high mowing speeds is important to doing a professional mowing job and, with the dual lever or joy stick control, bouncing over the terrain causes untoward motion of the levers and erratic steering control.